I am pretty sure it just depends on your leadership. Miguel can recruit him as soon as you encounter him. It still plays the audio file for Mike needing a medic, but then quickly changes to him bein' all about the money.

It seems that Mike have could use some further tweaks in XML - he have no old skills set and no full name other than simply "Mike" (at least in XML). Also, Attitude/Trait are left untouched, and need for sleep and dialogue approaches are on their default values.